Sybase announced on Wednesday that it is making available an Express Edition of its Adaptive Server Enterprise (ASE) 12.5.2 database for Linux.

The version, called ASE Express Edition for Linux, offers core ASE 12.5.2 functionality but will only work on a single-processor machine, storing a maximum of 5GB of data and using a maximum of 2GB of RAM.

David Jacobson, a marketing director at Sybase, said on Wednesday that this database has been produced for customers who want to run a test pilot of a commercial database on a Linux box.

"Many of our customers use Unix machines and want to move to Linux," said Jacobson. "As they are constrained by budget they are using free open-source databases to try Linux out, but we want to give them the opportunity to try ASE."

"We are the first company to provide a production database for Linux free of charge."

Sybase is providing a free licence for ASE Express Edition for Linux, but is not releasing the source code of the database. Jacobson believes that releasing the source code is not as important as reducing costs.

"Customers are looking for a way of getting a free database. They are not that interested in being able to view source code."

Jacobson said there are various issues surrounding open-source databases that he believes will draw customers towards Sybase's free database.

"ASE offers various enterprise features such as high availability, security and replication." Referring to the MySQL database which is available under parallel commercial and open-source licenses, Jacobson was critical of the Swedish company's business model: Businesses can -- and are encouraged to -- write open-source applications for the MySQL database, and in such cases are able to redistribute MySQL for free under the GPL licence. But those who want to write proprietary applications that use the database must pay MySQL a licence fee to redistribute the database with those applications.

Another open-source database, PostgreSQL, is released under the BSD licence, meaning that companies do not need to pay a fee as long as they insert a copyright notice.

However, although the Sybase licence is being given away for free, it is only for internal use by "employees, agents and contractors". The database cannot be sold or distributed in any way to third parties without Sybase's prior written consent, and cannot be used for "timesharing, rental or service bureau purposes," indicating that a Web site built on the free version of the database would be out of the question.

Jacobson claims that open-source databases have not been proven commercially compared with Sybase's database. "The ASE database is our flagship database. It has been around for 20 years, with 40,000 production customers."

Sybase carried out a performance study on ASE in HP's labs. The study found that ASE is the fastest database on a four-CPU Linux system, but it's not clear what it was tested against. ASE Express Edition for Linux will only work on a one-CPU system but Jacobson points out that customers can migrate from Express to the Small Business Edition, which allows them to use more CPUs.

Jacobson claims that various industry analysts, including a Gartner analyst, said that the product is likely to have reduced the number of businesses using open-source databases. Gartner was unable to confirm this.

Simon Riggs, a PostgreSQL developer, said on Thursday that he is not worried about the impact that ASE could have. Instead, he sees it as another sign that companies are worried about the impact of open-source databases.

"It is not a threat at all," said Riggs. "In fact, it is a good sign. Companies obviously see free, open-source databases such as PostgreSQL as such a serious threat that they are going out of their way to produce a free database."

Riggs claims that PostgreSQL is on the up, with ever-increasing downloads and increasing numbers participating in the developer community. On Thursday the general mailing list for PostgreSQL had over 2,000 subscribers and over 1,600 messages had been posted in the last 30 days, according to its Web site.